package com.thejupitech;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collections;
import java.util.WeakHashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

public class ImageLoader {
	MemoryCache memoryCache = new MemoryCache();
	FileCache fileCache;
	private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	ExecutorService executorService;
	
	public ImageLoader(Context context) {
		fileCache=new FileCache(context);
		executorService=Executors.newFixedThreadPool(5);
	}
	
	final int stub_id=R.drawable.default_img;
	public void DisplayImage(String url, ImageView imageView) {
		imageViews.put(imageView, url);
		Bitmap bitmap= memoryCache.get(url);
		if(bitmap!=null)
			imageView.setImageBitmap(bitmap);
		else {
			queuePhoto(url, imageView);
			imageView.setImageResource(stub_id);
		}
	}
	
	public void queuePhoto(String url, ImageView imageView) {
		PhotoToLoad p = new PhotoToLoad(url, imageView);
		executorService.submit(new PhotosLoader(p));
	}
	
	
	//Task for the queue 
	private class PhotoToLoad {
		public String url;
		public ImageView imageView;
		public PhotoToLoad(String u, ImageView i) {
			url = u;
			imageView = i;
		}
	}
	
	class PhotosLoader implements Runnable {
		PhotoToLoad photoToLoad;
		public PhotosLoader(PhotoToLoad photoToLoad) {
			this.photoToLoad=photoToLoad;
		}
		public void run() {
			if(imageViewReused(photoToLoad))
				return ;
			Bitmap bmp = getBitmap(photoToLoad.url);
			memoryCache.put(photoToLoad.url, bmp);
			if(imageViewReused(photoToLoad))
				return;
			BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
			Activity a = (Activity) photoToLoad.imageView.getContext();
			a.runOnUiThread(bd);
		}
			
	}
	
	boolean imageViewReused(PhotoToLoad photoToLoad) {
		String tag=imageViews.get(photoToLoad.imageView);
		if(tag==null || !tag.equals(photoToLoad.url))
			return true;
		return false;
	}
	
	private Bitmap getBitmap(String url) {
		File f = fileCache.getFile(url);
		
		//from SD cache
		Bitmap b = decodeFile(f);
		if(b!=null)
			return b;
		
		//from web
		
		try {
			Bitmap bitmap=null;
			URL imageUrl = new URL(url);
			HttpURLConnection conn=(HttpURLConnection)imageUrl.openConnection();
			conn.setConnectTimeout(30000);
			conn.setReadTimeout(30000);
			conn.setInstanceFollowRedirects(true);
			InputStream is = conn.getInputStream();
			OutputStream os = new FileOutputStream(f);
			Utils.CopyStream(is, os);
			os.close();
			bitmap = decodeFile(f);
			return bitmap;
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}
	
	private Bitmap decodeFile(File f) {		
		try {
			//decode image size
			BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			BitmapFactory.decodeStream(new FileInputStream(f), null, o);
			
			//find the correct scale value. It should be the power of 2
			final int REQUIRED_SIZE=80;
			int width_tmp=o.outWidth, height_tmp=o.outHeight;
            int scale=1;
            while(true) {
            	if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
            		break;
            	width_tmp/=2;
                height_tmp/=2;
                scale*=2;
            }
            
            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize=scale;
            return BitmapFactory.decodeStream(new FileInputStream(f),null, o2);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}
	
	//Used to display bitmap in the UI thread
	class BitmapDisplayer implements Runnable {
		Bitmap bitmap;
        PhotoToLoad photoToLoad;
        public BitmapDisplayer(Bitmap b, PhotoToLoad p)	{
        	bitmap=b;
        	photoToLoad=p;
        }
		public void run() {
			if(imageViewReused(photoToLoad))
				return;
			if(bitmap!=null)
				photoToLoad.imageView.setImageBitmap(bitmap);
			else
				photoToLoad.imageView.setImageResource(stub_id);
			
		}
		
	}
	
	public void clearCache() {
        memoryCache.clear();
        fileCache.clear();
    }
}
